A tool for burring the surface of a material. The tool has two sets of oppositely facing toothed blades which are made to move towards each other when the tool is pressed against a surface. Each tooth planes a shallow groove into the surface which results in hook-like burrs or planings rising from each groove. Limiters on the blade stroke ensure that the raised burr is not severed. A spring returns the blades to their start position. The resulting surface therefore has a plurality of shallow, non-piercing stopped grooves with a like plurality of hook-like burrs. Such a modified surface provides increased surface area for electrochemical activity, and a mechanical grip to materials bonded thereto. The tool uses replaceable blade packs which snap into a permanent tool housing. The tool may be operated with a simple hammer blow or it may be rapidly driven into large or small areas of a surface by a manual and/or computer directed punch press.